The Winter Walk: A Journey Across the Frozen Mississippi River, 1936
#4 R. D. Schmickle of the U.S. Geological Survey prepares to operate a device that measures the speed of the Mississippi’s current on Feb. 22, 1936.
Places & People

The Winter Walk: A Journey Across the Frozen Mississippi River, 1936
#4 R. D. Schmickle of the U.S. Geological Survey prepares to operate a device that measures the speed of the Mississippi’s current on Feb. 22, 1936.
Places & People